When heat rises in the evening
Heat rising at the end of the day, cheeks that redden, warm palms and soles, sweating at night, a dry mouth on waking, nervousness, a tired lower back… In TCM, these signs may be associated with Kidney Yin deficiency accompanied by Deficiency Fire. Yin, the cool, moist side of the body, normally keeps Fire in its place, as water tempers a flame; when it runs low, this Fire rises “without roots”.
Da Bu Yin Wan is the work of Zhu Danxi (朱丹溪, 1281-1358), one of the four great masters of the Jin and Yuan dynasties and the founder of the Yin-nourishing school. It appears in the Dan Xi Xin Fa (《丹溪心法》), the collection of his teachings compiled by his disciples, where it is simply called Da Bu Wan. There Zhu Danxi defends his thesis: Yang is always in excess, Yin always insufficient. His anemarrhena and phellodendron pair is found again in Zhi Bai Di Huang Wan, and it was in response to this school, which he considered too cold, that Zhang Jingyue later composed You Gui Wan.
Strengthening Water to master Fire
The formula responds on two fronts, what tradition calls cultivating the root and clearing the source. Prepared rehmannia, the most heavily dosed herb, nourishes the Yin and the Essence: this is the root. Anemarrhena and phellodendron form the pharmacopoeia’s most famous pair for Deficiency Fire: both are bitter and cold, but one moistens while the other dries, and together they bring the Fire down without drying.
Nourishes Kidney and Liver Yin: Sweet and rich, prepared rehmannia replenishes the Yin and the Essence, on which the whole balance of the formula rests.
Clarifies Heat: Bitter and cold, anemarrhena and phellodendron bring the Deficiency Fire back down, while rehmannia restores the Yin’s coolness.
Restores Yin-Yang balance: By restoring the Yin’s strength, the formula allows it once again to keep the Yang in its place: Water regains its measure over Fire.
